In operation, track laying work machines are subject to some of the most severe operating environments. In particular, the track chain assemblies of such work machines operate in continuous contact with abrasive, and occasionally corrosive, soil environments. Such track assemblies include pin and bushing joints positioned between adjacent pairs of track links to hingably couple the pairs of links. Each pair of links, in turn, carry ground-engaging track shoes. The pin and bushing joints are subject to extreme wear from the abrasive and corrosive soil environment and incur high stresses through the support of the track laying work machine and the engagement with drive sprockets.
Attempts have been made to increase service life of such track assemblies by improved metallurgy, factory sealing, lubrication of the joints, and by providing factory-assembled joints in serviceable form. Examples of such designs are disclosed in U.S. Pat. No. 3,958,836 issued to Brown on May 25, 1976 and U.S. Pat. No. 3,762,778 issued to Boggs et al on Oct. 2, 1973 that have proved effective in obtaining increased component life.
The arrangement disclosed in Brown, however, has a high production cost due to drilling a hole through the pin, tapping both ends, plugging one end and counter boring the opposite end and then placing a fitting in the counter bore. The counter bore is an attempt to protect the fitting by placing the fitting deeper within the pin. However, this arrangement allows material to collect in the void around the fitting and erode the fitting. At a minimum the material build up will compact and harden, which will require cleaning before replacement lubricant can be injected into the pin.
Boggs, on the other hand, discloses a much more efficient design that uses an elastomeric stopper placed in one end of a track pin. The stopper has a through hole in which oil is injected and an additional plug that is positioned in the through hole of the stopper to retain the fluid. However, this design requires the track to be removed from the machine and placed on its side to effectively fill the hollow pin with oil. Excess air is then allowed to escape through a passage in the stopper. A second stopper is then positioned in the passage to retain the oil.
The present invention is directed to overcome one or more of the problems as set forth above.